Television apparatus



Aug. 10, 1937. D,:v0N HA 2,089,588

TELEVISION APPARATUS Filed Nov. 23, 1933 3 Sheets-Sheet 3 Patented Aug.10, 1937 PATENT OFFICE TELEVISION APPARATUS Dnes von Mihaly, Berlin,Germany Application November 23,1933, Serial No. 699,471 In GermanyNovember 26, 1932 6 Claims.

My invention relates to a television scanning apparatus.

This application is a continuation in part or my former application Ser.No. 602,972 filed April 4th, 1932, entitled Television apparatus.

An object'of the parent application is to describe scanning apparatuscomprising a stationary member provided with peripherally disposedscanning elements for analyzing or recombining 10. an image, and arotary reflector for projecting :the image onto the analyzing member, orfor receiving an image from the recombining memher, as the case may be.With the apparatus there described the scanning member consists of adrum having ahelical row of apertures being encircled by a circle-shapedor helical photocell "or light relay. Another object of the parentapplication is to provide the scanning apparatus .with a photocell orlight relay of small dimenr sions arranged on the optical axis of it, incombination with a conical reflector surrounding the scanning drum, andwith another conical reflector which by means of a second rotary mirrorreflects the full light of the light relay to each single just actingaperture of the scanning drum. It has been found, however, that it israther diflicult to concentrate the whole available light on eachaperture having an area of say 1/100 square millimeter so thatconsiderable light lossescould not be avoided with the above deaotscribed arrangement.

One object of my present invention is to improve the light efiiciency ofthe scanning apparatus described in the parent application.-

; Another object is to replace the drum having a helical row ofapertures of this scanning apparatus by a stationary mirror-ringconsisting of a number of mirrors equal to the number of lines .intowhich the image has to be scanned, the

4 mirrors of this ring being faced towards the centre rotary mirror. 7With this arrangement the light has to be concentrated on each mirrorhaving an area of several square centimeters instead of the 1/100'square millimeter of an aperture, so that this concentration can beobtained by much simpler and cheaper optical means. ,Further, the mirrorring itself can also be produced much easier than the drum with theextremely small apertures; moreover, here the con- Y ical mirrors andthe second rotary mirror are rendered unnecessary.

The mirror ring may consist of plane mirrors being inclined underdifferent angles to the axis of the ring, whereat the scanning of theimages into lines is dependent upon the inclinations of the singlemirrors with respect to each other and to the axis of the ring.

In the accompanying drawings apparatus embodying my invention areillustrated diagrammatically by way of example.

Figs. 1 and 2 show a scanning apparatus provided with a mirror ringconsisting of plane mirrors.

Fig. 3 is another embodiment of my invention showing an improved form ofthe apparatus :shown in Figs. 1 and 2 and Fig. 4 shows a furtherimproved form of the apparatus according to Fig. 3.

Referring now to Figs. 1 and 2, the scanning device consists of a mirrorring formed by plane 15 mirrors H] which are mounted between the edge ofa disc H and a ring [4 by screws l3. The ring 14 is secured to the discH by arms I5 and screws l6 and has a larger diameter than the disc I I,so that the mirrors II] are inclined to the axis oi the ring. The angleof this inclination of .each single mirror can be adjusted by the screws13, and the mirrors are so arranged that, going in clockwise direction,each mirror is somewhat more or less inclined to the axis than theforegoing mirror. For scanning an image f. e. into 48 lines there are 48mirrors, one of them 1 being inclined to the axis at 45, the inclinationof each following mirror being about 12- less than of the foregoingmirror.

The light beam originating from the source of light 30, after havingbeen polarized by the Nicol prisms 3| and modified by the Kerrcellaccording to the impulses or the transmitted and received picturecurrents, falls through the 5 lens 25 upon the angle mirror 18 where itis projected to the rotary mirror 24 driven by the motor 19. From therotary mirror the light beam is reflected by way of the conical mirror23 to the mirrors In which project it on to the "'4 rotary mirror 3. Bythis rotary mirror the light beam is reflected to the angle mirror 20where .it is projected through the lens 2| onto the screen 26 upon whichthe single picture elements thus projected will apparently be assembledto' the whole image. The entire scanning device is mounted upon a frame32.

.necessary with the apparatus according to the parent application forerecting the image can be i omitted, and-therefore is not shown.

Fig. 3 shows a further embodiment of my in-' 755 =25 jects it to thescreen 25.

vention in which also the last angle mirror is removed, so that thelight losses are even more reduced.

This scanning device consists also of a mirror 5 ring having differentlyinclined mirrors 10, like the apparatus shown in Figs. 1 and 2, but herethe motor is placed in the centre of the mirror ring and the tworotating mirrors 3 and 24 are placed somewhat outside of the mirrorring. 10 This mirror ring is formed so that one of its mirrors 4!] isparallel to the axis of the ring and I each subsequent mirror incounterclockwise direction is inclined a little more to the axis of thering so that the mirror 4| being next. tothe 15 mirror 40 in clockwisedirection has the maximal inclination.

The light of the modulated light source 4.2 is concentrated by the lens43 upon the aperture 44 of the mask 45, said aperture having the area 20of one picture element. The image of this brilliant aperture is thrownby the lens 46 upon the rotary mirror 24, then reflected upon one of the.mirrors l of the mirror ring, and therefrom back to the other rotarymirror 3 which pm- It is obvious that, owing to the double sided mirrors3 and 24, during one revolution of these mirrors each mirror [0 will beilluminated twice so that the whole image will-appear also twice on thescreen in the same period. Thus, if the mirrors rotate w ring, and, inconsequence thereof, increase of the length of the way of the light rayswithin the apparatus whereby the light losses are increased again.

Fig- 4 shows a possibility for increasing the #15 area of the mirrors l0without a corresponding increase'of the diameter of the apparatus.

The mirror-ring is here subdivided into two parts 4"! and 48, each partcomprising half as many mirrors as picture lines are wanted. Both .450mirror rings are illuminated by the same source of light. 42' andproject the light upon the same screen 25 in such manner that the lightcoming from the ring 4'! illuminates the upper part and the light comingfrom the ring 48 illuminates the .55 lower part of the screen.

In order to avoid the simultaneous action of the two mirror rings thetwo rotary mirrors 49 and 50 are silvered only on one side, i. e. onopposite sides. Accordingly the inclination of the 60' mirrors of themirror ring is such that, begin ning with the mirror each subsequentmirror of the upper mirror-ring is inclined somewhat 'more, up to themirror 52, from which the increase of the inclination is continued withthe ...65 mirror 53 of the lower mirror-ring, up to the last mirror54"of this ring. a

If both rotary mirrors 49 and 50 are simultaneously illuminated by theglow-lamp 42 then each of them sweeps the light say once round 70 therespective mirror ring during one half revolution- Considering, thatonly one side of the rotary mirrors is silvered, during one fullrevolution of these mirrors all mirrors of both mirrorrings willbe'illuminated once, firstly those of V 75 the upper ring and then thoseof the lower ring.

They reflect the light to one of the prisms 55 which conduct it to thecorresponding half of the picture area on the screen 26.

Of course it is also possible to use this arrangement for transmittingpictures in two zones 5 if each rotary mirror is cooperating with aseparate glow-lamp. In this case it is advantageous to use rotarymirrors being silvered on both sides, in order to increase the number ofpictures per second.

Having now particularly described and ascertained the nature of myinvention and in what a manner the same is to be performed, I declarethat what I claim is:

1. Television apparatus, comprising a rotary reflecting means comprisinga reflecting surface which is substantially parallel to its axis ofrotation, and a plurality of stationary mirrors circumferentially spacedaround the axis of said reflecting means and cooperating therewith forscanning, said stationary mirrors being inclined to the axis of saidrotary reflecting meansat dif ferent angles and their number being equalto the number of lines into which the. image to be transmitted isscanned, said reflecting surface lying within the space defined by thetwo planes of theedges'of said mirrors.

2. Television apparatus, comprising two rotary reflecting means adapted.to be rotated together about the same axis, and a plurality of istationary analyzing elements for analyzing and recombining an imagecircumferentially spaced about the axis of said means, said elementscomprising plane-faced mirrors facing said reflecting means andcooperating therewith for scanning, said mirrors being arranged in tworings encircling said two rotary reflecting means, said mirrors beinginclined to said common axis of said rotary reflecting means, the angleof inclination of said mirrors increasing continually by. .f1 the samevalue from the first mirror of the first set of mirrors to the lastmirror of the same set, then from said last mirror of the first set tothe first mirror of the second set and on to the last mirror of thesecond set. 15 5 3. Television apparatus, comprising tworotaryreflecting means-adapted to be'rotated together about the same axis, anda plurality of stationary analyzing elements for analyzing andrecombining an image circumferentially spaced abOufi the axis of saidmeans, said elements comprising plane-faced mirrors facing saidreflecting means and cooperating therewith for scanning, said mirrorsbeing arranged in two rings encircling said two rotary reflecting means,said rotary re-. flecting means comprising two mirrors silvered onopposite sides and cooperating with a common source of light.

4. Television apparatus, comprising two rotary reflecting means adaptedto be rotated togethenlfiO about the same axis, and a plurality ofstationary analyzing elements for analyzing and recombining an imagecircumferentially spaced about the axis of said means, said elementscomprising plane-faced mirrors facing said reflecting means-= andcooperating therewith for scanning, said mirrors being arranged in tworings encircling said two rotary reflecting means, said rotaryreflecting means. comprising two mirrors silvered on both sides and eachcooperating with a separate source of light. 1

5. Television apparatus comprising a stationary substantially circularmember having spaced about it peripherally a plurality of mirrorsrelatively positioned for scanning, and means includ ing reflectingmeans mounted to rotate about an axis substantially parallel to the axisof said member and having every element of the reflecting surfaceextending in the direction of the axis substantially linear and parallelto said axis, to provide by reflections from said reflecting meansoptical paths progressively established between contiguous areas of ascanned field and said mirrors in succession as well as between saidmirrors and light source.

6. Television apparatus comprising a stationary substantially circularmember having spaced about it peripherally a plurality of mirrorsrelatively positioned for scanning, and means including reflecting meansmounted to rotate about an axis substantially parallel to the axis ofsaid member and having every element of the reflecting surface extendingin the direction of the axis substantially linear and parallel to saidaxis, to provide by reflection from said reflecting means optical pathsprogressively established between contiguous areas of a scanned fieldand said mirrors in succession as well as between 10 said mirrors and aphotoelectric cell.

DENEs VON MIHALY.

